Field of Invention
The present invention relates generally to a retractable nose cone apparatus for use with a hollow helical piling system and terminal helical anchor and methods for placing or installing either (i) reinforced concrete piles in situ without utilizing a pile driver or an auger, without unnecessary sacrifice of materials, and with the opportunity for efficient use of a terminal helical anchor and/or (ii) an electrical grounding system using a copper-bonded helical anchor and grounding grout.
Conventional Art
Pilings are often used to support buildings, bridges, antenna structures, and other structures—some of which also require electrical grounding. Pilings are known as either compression or tension pilings depending on whether the pile is designed to withstand forces that tend to push it into the ground (i.e., a compression pile) or pull it out of the ground (i.e., a tension pile). Conventionally, reinforced concrete piles have been placed or poured in the ground by one of two methods. The first method pours a precast reinforced concrete pile into the ground by using a pile driver and hammering the pile into the ground. The second method places a reinforced concrete pile in situ by drilling a circular hole into the ground using an auger, removing the soil, placing a pre-assembled steel reinforcing rod cage into the hole and pouring wet concrete into the hole to encase the steel reinforcing rod cage.
By contrast, conventional helical piling systems typically include one or more hollow metal helical pipes or screws or helices. The metal shaft or casing is rotated via a surface torque motor to force the helical screw downward into the earth until the screw is seated in a region of soil sufficiently strong to support the load or withstand the pull from the structure that it is to support. Additional pilings or metal casings can be attached or spliced to a previously screwed piling or metal casing to increase the depth of the overall piling. To accomplish this, adjacent round or circular ends of the pilings are usually reconfigured to have a generally square shape with rounded corners. The adjacent ends are configured to have male and female cross-sections so that the piles slide together forming a telescoping joint and are spliced to make a continuous piling.
U.S. Pat. No. 6,814,525 issued to Whitsett discloses a conventional helical piling apparatus and installation methods. The Whitsett patent discloses in its Abstract, for example, that an “in-situ pile apparatus includes a helical anchor to which a plurality of elongated generally cylindrically shaped sections can be added. Each of the sections has a specially shaped end portion for connecting to another section. An internal drive is positioned in sections inside the bore of each of the connectable pile sections. The internal drive includes enlarged sections that fit at the joint between pile sections. In one embodiment, the internal drive can be removed to leave a rod behind that defines reinforcement for an added material such as concrete. The rod also allows for a tension rod connection from the anchor tip to an upper portion attachment point.”
Another conventional helical pipe piling apparatus is distributed by MacLean Dixie HFS. It is like a large hollow cylindrical metal screw with a conical nose assembly (“nose cone”). Once seated in the ground, this hollow piling apparatus could be filled with reinforcing rods and wet concrete; however, the valuable steel pipe casings and nose cone would remain in the ground. A conventional helical pipe piling apparatus is disclosed in U.S. Pat. No. 5,833,399 and involves a single or “one [long] extension member” and the use of an expensive, tall, and difficult to transport drilling rig and pump truck. Because of the fact that the wet cementitious material must be applied through the single extension member to the unlined hole under pressure, this complicates the difficulty and expense of connecting multiple sections.
In view of the problems with conventional pilings, a piling method and system which is portable, which does not sacrifice expensive construction materials by leaving them in the ground, and which also permits the installer to independently measure and increase the torque of a terminal helical anchor, are needed in the art.